Format

Send to

Choose Destination
Dev Dyn. 2007 Jun;236(6):1570-82.

Nuclear accumulation of beta-catenin and transcription of downstream genes are regulated by zygotic Wnt5alpha and maternal Dsh in ascidian embryos.

Author information

1
Department of Biological Sciences, Graduate School of Sciences, Osaka University, Osaka, Japan. narudo.kawai@obs-vlfr.fr

Abstract

Nuclear beta-catenin plays crucial roles in the establishment of the embryonic axis and formation of mesendoderm tissues in ascidians and other animals. However, the cue responsible for nuclear accumulation of beta-catenin in the vegetal hemisphere is still unknown in ascidians. Here, we investigated the roles of Wnt5alpha and Dsh in the nuclear accumulation of beta-catenin and activation of its downstream genes in the ascidian Halocynthia roretzi. Wnt5alpha knockdown embryos lost nuclear accumulation of beta-catenin at the 64-cell stage but not at the 32-cell stage, and expression of Hr-lim, one of the targets of beta-catenin, was impaired in the anterior region of the embryo. Zygotic Wnt5alpha expression in the anterior-vegetal blastomeres was primarily responsible for these defects. Dsh knockdown showed no effect on nuclear localization of beta-catenin, but inhibited Hr-lim expression in the posterior region. These results suggest that maintenance of nuclear Hr-beta-catenin after the 64-cell stage is regulated by zygotic Hr-Wnt5alpha, and that expression of its target genes is modulated by both Hr-Wnt5alpha and Hr-Dsh. Our results also highlight the importance of nuclear accumulation of beta-catenin up to the 32-cell stage through a still unclarified mechanism.

PMID:
17474118
DOI:
10.1002/dvdy.21169
[Indexed for MEDLINE]
Free full text

Supplemental Content

Full text links

Icon for Wiley
Loading ...
Support Center